For many years, thermoplastic bags have been widely used for a number of household and industrial purposes. Many bags have a simple rectangular structure comprising two layers of thermoplastic film heat sealed at the bag bottom, folded sides and an open top. This simple structure has been adapted to form a wide variety of sizes and configurations that vary with the intended uses of the bags.
In recent years, bag manufacturers have developed new types of thermoplastic bags such as, for example, draw tape bags, handle bags, and bags with protruding top edges. These different bag types provide the user with different advantages such as being able to easily close, tie and/or identify a bag. However, the easy to open, use and close handle bags have traditionally required expensive and complicated manufacturing procedures. Furthermore, handle bag manufacturers have experienced cost reduction pressure from other products and, as a result of their cost reduction efforts, new product configurations have been developed. These new handle bag configurations have decreased the manufacturing costs of the product but have also made the resulting bags more difficult to open and use.
For example, one existing low cost handle bag configuration is produced by starting with a thin thermoplastic film tube that is transversely heat sealed to form individual bags. The tube is then double folded. Specifically, the edges of tube are longitudinally folded inward so that the edges are adjacent to the middle of the bag. The tube is then folded again about its middle thereby forming four overlapped bag sections comprising eight layers of thermoplastic material. A corner of the bag is then removed to form the handles and bag mouth. Such a manufacturing process is described and illustrated in U.S. Pat. No. 4,790,467.
However, the above described manufacturing process makes the resulting handle bag difficult and time consuming to open and use. A user must first unfold the second middle fold and then the first quarter folds in sequence before being able to open the bag. In addition, this method tends to trap air between the folded tube sections which further complicates the manufacturing process and reduces efficiency.
Consequently, these deficiencies have created a need for an inexpensive and efficient method of manufacturing handle bags that are easy to open, use and close.